Secondary battery.



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- ED STATES PAZFENTOFFICE.

EDWARD o. EKSTROMER ANDiisLcHEaEKsrRonEn, or sosf'rou,nassAcnusn'rrs,ASSIGNORS 'ro- JosEPH 0. mar, 'rnus'rue, or BOSTON, MASSACHUSETTS,

sncormlmyim'r'rnnv.

Patented April 20, i909.

- Application filedltay13f1907. Serial No. 373,444.

To all whom it'ma'y concern: f p r Be 1t known that we, EDWARD C. EK-STROMER 8.l1(l' ME QHER Exs'rnoiunn, subjects of the King of England andtheKing 5 of Sweden, respectively, and residents of v ful Improvement inSecondary Batteries, of,

Boston, in the county of- Suffolk and State of Massachusetts,haveinvented a new and usewhich the following'is'aspecitication. Ourinvention relates, to an in the structure of the-active material of. a

secondary. battery element, I whereby many V ofthe defects" foundexisting'batteries of this class'maybeovercome'.

f a secoiidary battery "as ordinarily constructed consists in general ofamet-allic oxid, formed into a paste in any suitable manner.v Suchactive material when in use exhibits certainworking defects such asbucklii'i ,sulfating, etc.) Attempts have heretofore been made'toovercome these defects by producing minute interstices or cavities inthe active material itself, with the end of thereby obtainingreater-freedom in the passing off of ga's'w 1en the battery is in Ioration. According to our experience, however, it has been found thatsuch a construction has for various reasons failed to accomplish thepurpose intended. Y

()ur improvement consists broadly and primarily in imparting 'to a massof active material thequalities of internal elasticity and porosity,whereby under the strain of The activematerial nished which facilitatethe release of as and fscribedis introduced into-the active element of asecondary battery, the said element possesses internal elasticity andporosity and 1S permissive of dialysis, whereby the defects now existingin the-ordinarysecondary battery plate are largely, if not entirely,remo.ved,' the tendencyv to buckling overcome, y 'sulfatin'g diminished,and the eflicientlife of t Y I 'said battery materiallyprolonged'.improvement I 'We will now proceedto describe what we believe to be thebest method of treatin the albuminoid and'alsofof the subse uentan--dling of the'resultant product-in t e production of the improvedsecondary battery plate 7 above mentioned.-

While we believe the r-results above 7o described may be obtained by thetreat- 'ment of albuminoid substances generally, yet we will take forthe specific purpose of the present description that fornrof albuminoidcommonly known as gelatin, which according to our preferred form ofprocedure we treat as follows: The gelatin is formed into a paste andthen formed into a filament of relatively minute cross-section. VVe' donot, however, desire to limit ourselves to so this specific method Ifprocedure, for the-- gelatin rnay be formed in an suitable manner intoany suitable shape, provided the resultant mass be sutliciently thin.The

mass is then treated with dilutesulfuric acid sufficiently long topermit of thorough percolation of the acid through the same. The massthus-impregnated with the suli'uric acid solution is then treated forthe reovercome the buckling tendency, am othc'r- 5 wise materiallyincrease the efiiciencv of the structure. The particular meansw rich wehave devised for obtaining such result consists in mixing with theactivematerial of a secondaiy battery a substance which so far as we areaware, is in itself novel apart hour the present application of it forthe pur )ose described. This substance consist-s 0 an albuminoid,preferably gelatin, {treated in the manner hereinafter set fn'thwhercbya portion of the elements nitrogen and hydrogen is removed Withoutchanging the consistency and physical, appearance of the albuininoid andleaving tie same porous, elastic and permissive of osmosis or dialysis--in other words, converting said albuininoid into a dialyzer of hi hdialtytic ower. We

have found that w on the su stance demoval of a portion of theelementshydro en and nitrogen, as thoroughly as practicable. We have found thata convenicniliand ellicient means .of bringing about this-removal is bytreating the mass with heat and water under pressure, pref thesuperficial acid. This may he done by placing the mass with water in ahermetic ally closed vessel so constructed that its contents may heraised to a high degree of heat, considerably above-the boiling point ofthe water employed and heating the same at a temperature of about 250degrees Fahr: for about half an hour. -\Chen the contents of the vessel,after such treatment are exams.

inonium sulfate \vhilea portion of the elements hydrogen and nitrogenwill be found to have been removed from the albuminoid,

rably after removing 95 ined, the water will he found to rontair am' aeraser l the consistency and-physical 'ap earance of which, however,have not .been c an ed and which isnow porous, elastic and big ly per;

missive of dialysis. In order to convenicntly unite the'albuminoid sotreated with the active material which'may be selected for the formationof a secondary batterg plate, the albumin'oid may be comminut andinechanicall .the battery b. preventing the comp ete formationor cargingof-the 'late, is converted durin charging into su lead oxid.urther, the plate whenformed will be elastic throughout and will befound to permit uniform self-contraction and self;-

' expansion and free release-of gasduring ondary battery.

structed is less efiicient and has a smalh-. r..v

' :active material containing matter which has. 'high dlalytic powerfor,

heavy charging and discharging.

The-suita of the charge of the attery an therefore may be bestdetermined emgiirically or experimen-' tally to suitthe con itions ofany particular case.

W'e are 'aware that heretofore it has been proposed to mix caoutchoucwith the active material of a com ressed plate of a secowever, a plateso .con-

discharge rate-in;' ampere-hours er square inch of positive surface thana p ate pasted with active material alone. The reason for this is thatcaoutchouc is a dialyzer onl to a certain limited degree for a fewetherea solutions-and has no dialytic power whatsoever for acidsolutions, and therefore it acts merelyus an adulterant when mixed withthe active material of a secondary battery plate, by reducing the amountof efiective active material without imparting thereto the compensatingadvantage of increased penetration of the acid electrolyte which is-effected by mixing with said active material matter of high dialyt 0power for acid solu-l tions, such for exam le as the modified albuminoidor gelatin escribcd herein.

We claim:

1. An active material for a secondary battery comprising a suitablemetallic oxid and an albuminoid' from which a portion of the nitrogenand hydrogen has been removed,

ric acid and le ratio of the active substance plate to the albuminoidsubstance will depend uppnthe out .ut or rate of dis-- leaving theconsistency and physical 1 appearance of said albuminoid-unchan'ged, andrendering the same elastic, porous and'permissive of dialysis. s.

2. An active material for a secondary battery comprisin a .suitablemetallic-oxid and gelatin from w ich a portion of the-nitrogen andhydrogen has beenremoved, leaving the consistencyand'physical ap'earance of said gelatin unchanged, and ten ering the same elastic,porous and permissive of. dialysis.

. 3.. A-secondarybattery element comprismg act'v'e. material mixedswithan albuminoidfrom which a portion'of the -nitrogen and hydrogenhas beenremoved, leaving the consistency, and hysicalappearanc'e of saidalbuminoid unc anged an rendering the 4.18. secondary batteryelement-com rising acti [material mixed with gelatin om same elastic,porous, and'permissive of di-. g 4

1whicha ortion-o f the nitrogen. and hydrogen has een removed,leavingthe consist- ;ency an physical appearance of said. gelatin'unchangedand-rendering the same elastic, porous,- and permissive of dialysis.

A secondary battery element having active ]material containing: elastic,porous matter of high dialytic power. A

6'. A secondary battery element having active material containingmatterof high dialytic power. a r

7. A secondary battery element having metallic oxid containing e ter ofhigh dialytic power.

8. A secondary metallic'oxid containing matter of high dialytic power.

.' 9. A secondary battery element having elastic, porous {acidsolutions. 1

- 10. A secondary batteryfelement having active material containingmatter which has high dialytic power for acid solutions.

11. A secondary battery element having metallic oxid containing elastic,porous matr ter which has high dialytic power for acid solutions. 1 10'12. A secondary battery element having metallic oxid containing matterwhich has h dialytic power for acid solutions.

11 testimony wheroef, we have hereunto subscribed our names this tenthday of May,

EDWARD C. EKSTBOMER. MELGHER EKSTROMER.

astic, porous 1nat- 95 attery element having

